DARLINGTON — Since construction ended on the Conowingo Dam in 1928, it has been the best management practice to prevent sediment flow into the Chesapeake Bay from the Susquehanna River, said Bob Judge, spokesman for Exelon.
Exelon is currently at the tail end of its seven- to nine-year relicensing process for the Conowingo Dam, a carbon-free, energy-producing dam that has been shrouded in controversy over the amount of sediment coming over the dam and harming the Chesapeake Bay.
If Exelon gets approved for the license, it would be allowed to operate the dam for another 46 years.
But Kimberly Long, senior program manager for hydro-relicensing, said sediment is only one aspect of the relicensing process, with other aspects including recreation opportunities, shoreline management process and a bald eagle management program.
Long said the process involves other agencies, both government and nongovernment, that are basically stakeholders in the dam, Bay or Susquehanna River, and are interested in the relicensing process.
For starters, Long said, Exelon was involved in 47 different environmental studies between the dam and its sister dam, Muddy Run, which looked at factors like water flow, fish passage and mortality rates.
Exelon is participating in a sediment study on the Lower Susquehanna River Watershed, which is a three-year ongoing study started in September 2011 that looks at options for managing sediment in the watershed and is being coordinated by the U.S. Army Corps of Engineers.
Judge said the 14-mile pond behind the dam traps about two-thirds of the sediment that comes from the Susquehanna River on an annual basis.
“Obviously, the Lower Susquehanna River Watershed Assessment is a very important venue for Exelon to work with many different agencies and partners at looking at the issue that is of significance to the Chesapeake Bay,” Long said.
Michael Bruce, director of the resource assessment service at Maryland Department of Natural Resources, which is involved in the Lower Susquehanna River Watershed Assessment by providing some non-federal money to fund the study, said the study is trying to cover all options for taking care of the sediment issue at the dam.
“We understand that this is a huge issue and … there’s not one single silver bullet that’s going to be able to solve the problem,” Bruce said.
He said researchers are currently evaluating multiple strategies and trying to determine which ones are actually feasible, but they won’t implement any sediment removal, as the study is just to lay out what the strategies are and associated general costs.
Ready for environmental analysis
Some things Bruce said researchers are looking at are dredging, potential, beneficial reuses and lightweight aggregate creation of sediment, and also times of the year for sediment release that might not be as detrimental to the habitat and the Bay.
“(We’re) looking at what about if we release some of the sediments and do some sediment bypass around the dam, because the area right below the dam is actually starved for the core … material that is great fish habitat,” Bruce said.
Though the study is associated with the relicensing of the dam itself, Bruce said it can shed some light on provisions of Exelon’s license and what its best management practice responsibilities would be.
Long said most of the sediment in the Bay does not come from the Susquehanna River, but is actually from other sources like the Potomac River and the Rappahannock River.
She said it is known that sediment comes from upstream of the Bay, in the Susquehanna River’s 27,500 square miles of watershed. Any time a storm event happens, stream channels will naturally erode just from the sheer volume of water being pushed through.
That’s why Long said source reduction is an important strategy for a healthy Bay.
“(It) just means where you’re doing stream restoration best management practices so you’re keeping the cows out of the stream, you’re putting in riparian buffers, because trees and shrubs are very important to helping stabilize those banks that would otherwise be eroded,” Long said.
Overall, those practices take time to show an improvement in waterway health, she said.
“I think often it’s easy for humans to want to see a change immediately, because that’s how we respond to things, but stream restoration really does do a benefit to the watershed,” Long said. “In that small area where the project happened you’ll see an immediate response, it just takes long to recognize that impact throughout the watershed.”
Right now, Long said Exelon is in the middle of the negotiation process with interested parties concerning their relicensing and what provisions of responsibility should be included in their license.
She said the Federal Energy Regulatory Commission stated on Monday that the Conowingo Dam and Muddy Run, which were applied for relicensing together by Exelon, are ready for environmental analysis, which sets a deadline, Sept. 30, 2013, for preliminary terms and conditions and when interested parties can get involved in the relicensing process.
“Between now and essentially July, we’ll continue to meet with various agencies and stakeholders who’ve been involved with the process thus far in the hope that we would reach a coordinated settlement and present that to FERC by Sept. 30,” Long said.